Instantaneous phenomena during the pulsed fiber laser welding of pure zirconium in a hyperbaric environment

The instantaneous evolutions of the molten pool and plasmas during the pulse fiber laser welding of pure zirconium (Zr) under different high pressure environment were explored. Furthermore, the mechanism and influence law of the increase of the pressure on the weld penetration of pure Zr were analyzed. The result indicated that the weld penetration of pure Zr significantly reduced with the ambient pressure's growth. That is because of it could lead to the strengthening of the shielding effect of plasmas generated during laser welding on laser energy and improve the evaporating temperature required to produce the recoil pressure. The research result can enrich the theory on laser process under hyperbaric conditions and is favorable for the development of the laser manufacturing technology in the nuclear industry.